dualshock 3 -> zsnes button converter

[clinton/scratch.git] / zsnes-dualshock3-buttons.scm

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+;;; Calculate ZSNES buttons for Dualshock controllers
+
+;; From: http://blog.brokenfunction.com/2009/07/zsnes-and-a-sixaxis-controller/#comment-56667
+;; Run zsnes and quit.
+;; Look for the lines (something like)
+;; Device 0 Sony PLAYSTATION(R)3 Controller
+;; 27 axis, 19 buttons, 0 hats, 0 balls
+;; Device 1 Sony PLAYSTATION(R)3 Controller
+;; 27 axis, 19 buttons, 0 hats, 0 balls
+
+;; Note the number of axes and buttons for controller 1 (first) and second (2).
+;; e.g. axes1, buttons1, axes2, buttons2
+
+;; Controller 1′s select button (base) will be 256 + (axes1*2)
+
+;; Controller 2′s select button (base) will be 256 + (axes1*2) + buttons1 + (axes2*2)
+;; Equivalently, it’s Controller 1′s base + buttons1 + (axes2*2)
+
+;; Unfortunately, you can’t use 3 controllers this way, because it has
+;; a hardcoded max offset of 448 (not sure why). It would have to be
+;; recompiled at least to get around this but that might be based on a
+;; dependency.
+
+;; You can see the logic for this in zsnes’s source code, in src/linux/sdllink.c in
+;; BOOL InitJoystickInput(void){}
+
+(define axis-count 29)
+(define button-count 17)
+
+(define (base-button) (+ 256 (* 2 axis-count)))
+
+(define (base-button-2)
+  (+ (base-button) button-count (* 2 axis-count)))
+
+(define (zsnes-buttons js-button)
+  (values (+ (base-button) js-button)
+         (+ (base-button-2) js-button)))
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